sudo apt-get install openssh-serveropenssh-server;openssh-server : Depends: openssh-client (= 1:6.1p

when you install openssh-server,

sudo apt-get install openssh-server

if there is showed :

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 openssh-server : Depends: openssh-client (= 1:6.1p1-4)
                  Recommends: ssh-import-id but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

This mean you must install  openssh-client (= 1:6.1p1-4).

You can install openssh-client (= 1:6.1p1-4) as follow:

sudo apt-get install openssh-client=1:6.1p1-4

Then you can see:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Suggested packages:
  libpam-ssh keychain monkeysphere openssh-blacklist openssh-blacklist-extra
The following packages will be DOWNGRADED:
  openssh-client
0 upgraded, 0 newly installed, 1 downgraded, 0 to remove and 0 not upgraded.
Need to get 948 kB of archives.
After this operation, 985 kB disk space will be freed.
Do you want to continue? [Y/n] y
Get:1 http://old-releases.ubuntu.com/ubuntu/ raring/main openssh-client amd64 1:6.1p1-4 [948 kB]
Fetched 948 kB in 8s (116 kB/s)                                                
dpkg: warning: downgrading openssh-client from 1:6.6p1-8 to 1:6.1p1-4
(Reading database ... 168218 files and directories currently installed.)
Preparing to unpack .../openssh-client_1%3a6.1p1-4_amd64.deb ...
Unpacking openssh-client (1:6.1p1-4) over (1:6.6p1-8) ...
Processing triggers for man-db (2.7.0.2-2) ...
Setting up openssh-client (1:6.1p1-4) ...
Installing new version of config file /etc/ssh/moduli ...
Installing new version of config file /etc/ssh/ssh_config ...

next youcan install openssh-server !